Snubbing means for reciprocating elements



sePt- 1960 N. R. GUlLBERT, JR

SNUBBING MEANS FOR RECIPROCATING ELEMENTS Filed Oct. 7, 1957 ///////4 I I h I I I ll INVENTOR SNUBBING MEANS FOR RECIPROCATING ELEMENTS Nicholas R. Guilbert, Jr., Glenside, Pa., assignor to Guilbert, Incorporated, Philadelphia, Pa., a corporation of Pennsylvania Filed Oct. 7, 1957, Ser. No. 688,736

g Claims. (Cl. 16-82) The present invention relates to means for decelerating and arresting the motion of reciprocating elements and is particularly directed to snubbers or stops for vertically slidable elevator doors and the like, constituting an improvement over the snubbers disclosed in my prior copending application for United States Letters Patent Serial No. 585,815, filed May 18, 1956, entitled Snubbing Means for Reciprocating Elements, now Patent 2,894,275,

.granted July 14, 1959. V "In that application snubbers are disclosed comprising a pair of spaced bars having fulcrum means between them embraced by friction plates relatively slidable longitudirially of the bars and against which friction of the latter is adjusted by pressure means acting between the bars at points between their ends and the fulcrum means whereby the pressure exerted by the bars against the friction means in areas between the fulcrums is controlled.

In the present invention a single bar is preferably employed and the friction means embracing it are mounted for adjustment relatively thereto to thereby control the pressure between them in a manner to maintain this pressure at a substantially uniform value .per unit area ing somewhat more effective snubbing action than can readily be attained in the snubbers disclosed in said application.

It is therefore a principal object of the invention to provide an improved snubber for a reciprocating elevator door or like which is elfective to rapidly decelerate the door adjacent the respective limits of its travel so as to bring it to rest at such limits, respectively, quickly, quietly and with but a minimum of vibration, but which during the major part of the travel of the door, from initiation of its movement away from one limit and until just before its attainment of the other limit, is. without any restraining effect upon the doors motion.

Another object is to provide a snubber in which improved means for maintaining frictional pressure between relatively movable elements or components thereof enables such pressure to be kept substantially uniform throughout a relatively large area to thereby minimize wear and eliminate for long periods the necessity for .wear compensating adjustments to maintain full operational effectiveness of the snubber.

Other objects, purposes and advantages of the invention will hereafter more fully appear or will be under- ;stood from the following descriptionof certain embodi- United States Patent Office .throughout the zone of engagement between the friction means and the bar thereby minimizing wear and provid- Patented Sept. 13, 1960 ciprocating structure to which it may be attached fragmentarily indicated in broken lines;

Fig. 3 is a horizontal section on the line3-3 in Fig. 2 taken in the direction of the arrows on the section line, and

Fig. 4 is a fragmentary view generally corresponding to Fig. 1 showing another embodiment of the invention.

Referring now more particularly to the drawing, it will be understood that while a snubber is shown in Fig. 1 as if mounted on a reciprocally movable structure for engagement with fixed stops positioned adjacent the limits of travel of the latter, it may be utilized with equal effectiveness when mounted in a fixed position and suitably spaced stops or abutments are secured tothe reciprocating structure for alternate engagement with the snubber ends. a

More specifically, the snubber illustrated in Figs. 1-3 comprises a metal sleeve 1 preferably substantially rectangular in section having a plate 2 welded to one of its sides and provided with threaded holes 3 each adapted to receive a cap screw 4 for securing the sleeve to a supporting structure such as a vertically reciprocating ele' vator door D. Another side of the sleeve, preferably one adjacent that to which plate 2 is attached is provided with a pair of spaced holes 5 and a projecting threaded stud 6 positioned midway between them for reception of a spring pressure bar 7 and an adjusting nut 8 securing it thereto. Bar 7 near its ends is provided with shallow circular depressions or sockets 9 for reception of a pair of pins 10 which project thereinto through holes 5 inthe sleeve wall from an elongated plate 11 within the sleeve. These pins are preferably fitted into holes in plate 11 and permanently welded thereto during manufacture of the snubber, the welds being ground smooth with the face of the plate to present a plane surface for reception of a friction lining 15 which with a similar friction lining 16 on an inner wall of sleeve 1 embraces a relatively movable snubbing bar 17 extending lengthwise through the sleeve between said linings which are held to the plate and sleeve respectively by rivets 18. A pair of pad supports 19, 20 secured respectively by threaded cap screws 21 to either end of snubbing bar 17 are faced at their extremities with rubber or other suitable composition of material similar to that used for the linings of automotive brakes and comparable friction elements, the pressure exerted on bar 17 by the linings being susceptible of control by adjustment of nut 8 to provide the appropriate spring pressure through pressure bar 7 and studs 10 to plate 11. The latter is held in fixed position longitudinally of the sleeve by pins 10 and is desirably relatively rigid, while bar 7 also restrained by the pins from movement in a vertical plane about stud 6 is somewhat yielding, spring steel or the like being suitable for itsprodugi; tion, whereby constant spring tension is exerted against lining 15 on plate 11 through pins 10, and snubbing bar 17 is thereby forced against lining 16; as the linings are otherwise relatively fixed bar 17 is free to move vertically in respect thereto only in the sense that friction between it and the linings alone affords any restraint upon such movement. Hence considering the snubber as carried by door D positioned at the upper limit of its travel, with its upper shock pad engaging stop S and the lower portion of bar 17 projecting considerably beyond the lower end of sleeve 1 the door carrying the snubber with it may be moved toward the lower limit of its travel in the normal way, initially unaffected by the presence'of the snubber. As the lower pad 22 approaches stop S 'with which it is aligned, and engages it preferably short- 1y before the door attains said lower limit, the stop prevents further movement of bar 17 with the door which, however, remains free to move relatively thereto. The inertia of the door forces it to continue its motion, however, and sleeve 1, linings 15, 16 and associated elements carried with it therefore slide along bar 17 in opposition to the friction exerted between the linings and bar to bring the door to rest approximately at the lower limit of its travel and concurrently position the bar in the sleeve with its upper end projecting considerably above the upper sleeve end oppositely to the former relation of these parts, preparing the door and snubber for being moved in the opposite direction when the above actions are reversed on engagement of upper pad 22 with stop S. Thus on each snubbing action the snubber is automatically reset for a succeeding one and by appropriate adjustment of not 8 the frictional resistance to movement of the sleeve relatively to bar 17 may be fixed to cause the door to be decelerated by the snubber and brought to rest at precisely the desired open and closed positions without shock or jar.

In the embodiment of the invention illustrated in Fig. 4 elastic yielding means are utilized instead of spring 7 to maintain controlled pressure between friction linings and the snubber bar. More specifically, this snubber comprises a sleeve 1 suitable to be mounted on a reciproeating structure through provision of plate 2 welded to it but having interposed between movable friction lining and plate 11' which supports it an elastic strip 25 of appreciable thickness substantially coextensive with lining 15 and plate 11 and made preferably of a suitable elastomeric material such as neoprene. The rivets 18 holding lining 15 and strip 25 to plate 11' are preferably slightly loose in holes in the latter and thus are free to move axially therein when the strip is compressed. Spaced screws 6' threaded into the wall of sleeve 1 paralleling linings 15', 16' are received in small depressions in the outer face of plate 11 to inhibit lengthwise movement of the latter while affording adjustability which enables the pressure of lining 15 against snubbing bar 17 to be controlled. Elastic strip 25 is thereby maintained under compression to insure adequate frictional resistance to relative longitudinal movement between bar 17 and friction linings 15, 16'.

This snubber when installed as above described in connection with that shown in Figs. 1-3 and properly adjusted, operates in precisely the same manner as the latter to bring a door or the like gradually to rest at the limits of its travel, the two snubbers being substantially the same except for the differences in means for exerting and controlling yielding pressure against the movable one of a pair of opposed friction linings embracing a snubber bar.

It will be apparent, however, that if a reciprocating door equipped with a snubber of either type be moved from one limit position toward the other but returned to the latter before reaching the former the snubber may be partially or wholly ineffective through not having been reset but automatically becomes again fully operational upon the door later being moved the full distance toward the said opposite limit of its travel. Obviously a pair of the snubbers, one mounted on each side of a sliding door, may be employed if desired, and my snubbers may be used in an appropriate manner to decelerate and arrest the motion of substantially any reciprocating element, whether reciprocableon arectilinear-'or'anyother path although it is not especially adapted for use with elements which do not as a rule attain their limits of travel at each reciprocation.

While I have herein illustrated and described with considerable particularity one embodiment of the invention which I prefer and another which may be utilized in its stead if desired it will be understood that this is not to be deemed in any way as restricting or confining the invention thereto in any way as other modifications and changes in the form, construction and relationship of the several components and in their modes of cooperation will readily occur to those skilled in the art and maybe utilized if desired without departing from the spirit and scope of the invention as defined in the appended claims.

Having thus described my invention, I claim and desire to protect by Letters Patent of the United States:

1. In combination, a snubber for a reciprocating door or the like comprising a sleeve element having friction means secured to an inner surface of the sleeve, a bar element engaging said means, slidable longitudinally relatively to and having its ends projecting beyond the ends of the sleeve, one of said elements being adapted for securement to the door with the other movable relatively thereto, a second friction means in the sleeve engaging the bar oppositely with respect to the first friction means, yielding means urging the second friction means toward the first friction means to cooperatively embrace the bar between both said means, and spaced abutment means immovably disposed substantially in longitudinal alignment with said elements and respectively adapted to limit longitudinal travel in opposite directions of the element movable relatively to the door when the other of said elements is reciprocated with the door thereby effecting relative longitudinal movement between said elements.

2,. The combination defined in claim 1 including a plate secured to the second friction means in the sleeve, spaced pins carried by the plate extending through holes in the sleeve, and a leaf spring engaging said pins and connected to the sleeve between them.

3. The combination defined in claim 1 in which the bar element is the element movable relatively to the door and includes means carried by the ends of the bar adapted for alternate impingement against the abutment means to slide the bar longitudinally in respect to the sleeve.

4. The combination defined in claim 1 in which the yielding means comprise a strip of elastic material engaging the second friction means.

5. The combination defined in claim 4 in which a movable plate supports the yielding means and adjustable means threadedly engaging the sleeve supports the plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,560,594 McMahon Nov. 10, 1925 2,791,793 'Fenton May 14, 1957 FOREIGN PATENTS 102,303 Sweden Aug. 12, 1941 

